Enumerable.prototype.where = function(predicate) {
        var e = this.getEnumerator();

        return new Enumerable(function() {
            while(true) {
                if(!e.next())
                    return { finished: true };

                if(predicate(e.current()))
                    return { finished: false, val: e.current() };
            }
        });
    };

    Enumerable.prototype.select = function(selector) {
        var e = this.getEnumerator();

        return new Enumerable(function() {
            if(!e.next())
                return { finished: true };

            return { finished: false, val: selector(e.current()) };
        });
    };

    Enumerable.prototype.each = function(fn) {
        var e = this.getEnumerator();

        while(e.next())
            fn(e.current());
    };

    Enumerable.prototype.reverse = function() {
        var stack = [];
        this.each(function(x) { stack.unshift(x); });

        return new Enumerable(stack);
    };

    Enumerable.prototype.at = function(index) {
        var e = this.getEnumerator();
        var i = -1;

        while(e.next())
        {
            i++;

            if(i == index)
                return e.current();
        }

        return null;
    };

    Enumerable.prototype.len = function() {
        var e = this.getEnumerator();
        var len = 0;

        while(e.next())
            len++;

        return len;
    };

    Enumerable.prototype.array = function() {
        var a = [];
        var e = this.getEnumerator();

        while(e.next())
            a.push(e.current());

        return a;
    };